You can already give em customnames with colour (MSN 7 Beta +
Plus! beta for MSN 7 Beta). Just choose a colour you would like to use for male and another one for female.
Rightclick contactsname > plus extras > rename contact..in the screen that comes up give the contact a customname, and/or if you wanna keep the name they have put themselves name em (!N), highlight the part you wanna colour, hit ctrl+k..choose colour <enter>. All done